Fit for Mars

Tomatoes had unexpectedly become her main project. The tools felt familiar in her hands and the green vines were reassuring. Keeping them alive, fed and watered had occupied most of her attention for the past six months while travelling. Her fingers felt the pushback from the tomatoes’ flesh. “Not quite ready. Next week,” she said to herself.

Two years

A round trip to Mars and back is almost two full years. Having enough food is one problem but keeping healthy while the world watches is another.

There are only so many times you can have the same pre-packaged meals before they become boring. Even astronauts staying on the International Space Station lose weight due to menu fatigue. And while growing food on a trip to Mars would provide a fulfilling and stimulating task to combat mental stresses it’s important to remember staying healthy in spaces means looking after the mind as well as the body.

Fit body

In space everything is in free fall so it feels like there’s no gravity. Living in this microgravity environment causes the human body to change because it isn't working against the force of gravity.

"Your muscles have evolved to cope day to day with gravity on Earth,” says Phil Carvil, a researcher looking at how bodies react to space. “But in space you don't use them as much, so your body is thinking ‘why do I need this?’ and your muscles will deteriorate. Without the stresses and impact forces needed to maintain muscle and bone, you lose up to 20% of muscle mass each month, especially in the lower muscles – the back of the legs, the calves, and the spinal muscles."

Bones lose about 1% of tissue each month in space because of the smaller loads placed on them. The spine also responds to not being constantly pushed down by gravity, and the body can extend up to 70mm. This can be good if you always wanted to be taller, but can cause back pain.

Astronauts try to mitigate these negative effects on the ISS by exercising. "Physical training is something astronauts do on a daily basis in space for two hours a day. It's a mixture of cardiovascular and resistance exercises, and that helps to maintain fitness and stimulus on the heart, muscles and bones," Phil says.

New ideas are also being tested, including a skinsuit which uses stretchy material to compresses the body in a similar way to Earth's gravity.

But for a mission to Mars, you need to be able to function once you get there. "The gravity on Mars is one third of the gravity on Earth,” says Stefan Schneider, from the Institute of Movement and Neuroscience at the German Sport University, Cologne, who has been looking at the impacts of simulated space isolation. “It’s not so much about muscles and good bones – your weight is a third of what it would be on Earth. This is something we need to prepare for using specific entrance training programmes to keep people fit and able to perform their tasks on Mars."

Mindful of the mind

Apart from the body there's also the mind to consider. The Mars500 programme simulated a mission to Mars by isolating volunteers from the outside world for 500 days – even replicating the 20-minute communications delay that would occur over the actual distance to Mars.

"The main problem during such a journey is that you need to work as part of a multinational, multicultural team. There is a tremendous amount of work to do; you have to be precise while carrying out these activities, you have limited access to friends and family, the quality of food is not ideal – all these are factors that add stress on the psychological side," Stefan says. "What we need now are studies to see how we can counteract this stress to prevent problems during the flight and increase the success and safety of such a mission."

To ensure missions are a success, the selection process becomes more important. Potential astronauts are exposed to stressful situations, different cultures and different ways people approach problems – and how well they cope is assessed.

Although putting people in a dome for 500-plus days, or evaluating long spells living on the ISS, can tell us something about the stresses the human body and mind would go through on a trip to Mars, it's not possible to be certain that any mission would be a success. But given the fame and the indelible mark on history that would come with being one of the first people on Mars, would you still go?